A major problem in municipal maintenance is the replacement of deteriorated, underground, utility pipes which supply water and gas and remove sewage from individual households. The normal replacement technique is to dig a deep, wide trench, thereby exposing the pipe to be replaced. This trench follows the pipe from the center of the street, across the sidewalk, across any lawn and shrubs that are on the house lot, to the cellar of the house. The trench digging is not only costly and inconvenient, but also can be a source of danger to curious children and to workmen in the trench. There are instances, also, where obstructions are present where an excavation simply cannot be made, either mechanically or manually. Furthermore, there are situations where trenching can be accomplished only manually and in such situations the cost of pipe replacement is prohibitive in terms of time and cost.
An alternative to the standard approach is called "pipe pulling". This technique involves (1) freeing the inside end of the pipe in the cellar of the house, and (2) freeing the outside end at the center of the street by digging a small trench confined to the street and disconnecting the outside end of the pipe. A chain is then connected between the exposed outside end of the pipe and a drafting device, such as a tractor, and the pipe is pulled from the ground. By attaching a new pipe on the trailing end of the old pipe, a simultaneous replacement is effected. In the situations where this pulling technique can be effective, it still has two major problems. First, of course, there is the fact that, since the pipe is being removed because it has deteriorated, it often happens that the old pipe breaks half way through the operation leaving the residual section in the ground without either end exposed. Even if the residual section can be extracted by pulling it into the cellar on the attached new pipe, it is then usually impossible to implant a new pipe without using the trench method. A related problem, is the attachment of the replacement pipe to the trailing end of the old pipe. First, it is clear that this concept will place additional drag on the trailing end of the pipe and increase the likelihood of the old pipe breaking. This situation is aggravated by additional drag imposed by any connection between the pipes which is sufficiently strong to hold them together. Often, connections which were designed with low drag are not sufficiently strong to maintain the connection between the old and new pipe. The result is that the old pipe is extracted and the new pipe is not in place. Normally, the new pipe cannot be pushed through the remainder of the distance and the trench method must be used.
These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide a pipe remover which is capable of extracting a buried pipe with a minimum of excavation.
Another object of this invention is the provision of a pipe remover which minimizes the possibility of breaking the pipe to be removed.
A further object of the present invention is the provision of a pipe remover which permits the removal of the pipe even if it breaks during the operation.
It is another object of the instant invention to provide a pipe remover which provides a simple, effective, a low-drag-producing connection between the trailing end of the old pipe and a new replacement pipe.
A still further object of the invention is the provision of a pipe remover which is both simple and inexpensive to produce and flexible in the range of situations in which it is effective.
It is a further object of the invention to provide a pipe remover which performs its function at a minimum cost and with a minimum of destruction to surface structures.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.